Malaria Case Study Arlín Toro Rafael Tosado Cole Benton
Malaria Case Studies Potential Courses Study Aspect Case Scenario Resources/Activity • Maps • Basic concepts • Malaria Life Cycle • Travelers info. • WHO, CDC, NIH Case1 Malaria prophylaxis and control • Gen. Biology • Intro. Ecology • Gen. Microbiology • Parasitology Tempting family vacation package but no time for malaria prophylaxis • Gen. Biology • Microbiology • Parasitology • Bioinformatics • Genetics • Molec. Biology • Evolution • Bol Wrkbench • Case it • NCBI • Plasmo DB • CDC, WHO, NIAID Case2 Parasite-drug resistance and diagnosis challenges Aunt Milagros died of cloroquine- resistant malaria in 1982. Students collecting mosquitoes find Anopheles in a non- endemic area for malaria. • Gen. Biology • Parasitology • Ecology • Evolution • Population Biology • HIPRE • My World GIS • Transgenic • mosquitoes Case3 Ecology of the mosquito vector Student products: develop ilustrated materials to use w/ deaf people, five min. comercials on malaria prophylaxis, etc.
As he munched yet another piece of Christmas rice pudding Sebastián Román glanced about the gaily decorated room at his family. His brother’s children were busily, excitedly comparing the presents they had pulled from underneath their beds earlier in this celebratory Three King’s Day. Family, food, music, and the smell of ginger and cinnamon smoldering on the table and sending small fragrant wisps throughout the house made everyone happy. Not everyone, Sebastián thought as he noticed his father staring out the kitchen window, a deep sadness on his face. “What is it? Why aren’t you happy?” Sebastián inquired, approaching his father and pulling back the curtain so he could look out at what his father saw. “I’m OK,” he said. “ I was just recalling that when you were just a small niño, twenty years ago on this day, we lost Aunt Milagros. It’s the ginger smell, I guess, that does it, that makes me remember that sad, sad day. I loved my sister and I miss her deeply.”
“You never talked about what happened to her,” Sebastián said, putting his arm around his father’s shoulder. “What did happen?” Mr. Román pulled his son toward the table where they would soon enjoy the Feast of Epiphany on this, the last day of their Christmas. They sat down. “In a word, ‘malaria.’” Sergio Román told his son. “Malaria.” Román repeated. “It could have been anything. It happened, it took her from us and that was all that mattered. Still, I never really understood that disease.” Talking seemed to brighten Mr. Román. He enjoyed talking to this son who had flown home to their family from his university in the United States to share the holidays. Sebastián was a man now, a man a father could talk with.
“We hadn’t had malaria here in Puerto Rico for over twenty years when your Aunt Milagros died of it.” He went on, “She was using her teaching skills to educate children in the Amazon Chocó forest. Evidently she became infected on that trip and came home with the parasite already in her body.” • Sebastián’s mother Maria sat down beside her husband. She knew precisely what he would be talking about so seriously on this day, but she pretended ignorance. • “So, what are we discussing here?” • “Aunt Milagros,” Sebastián answered • “I should have known. Your father always, as I do, remembers your aunt’s passing on this day. Was he finally discussing it with you?”
“Yes, he told me about her missionary work in Colombia.” Sergio continued. “She took her antimalarial drug Chloroquine as a preventative, but it didn’t help. I just don’t understand.” “When she returned to Puerto Rico, she told us that she had had a fever the day before. The second day home here in Barranquitas she had it again. Then she had it again in two days after that. Your aunt insisted that the fever cycles were not, absolutely not, malaria because: ‘I took the drugs as required by the regimen exactly as I was supposed to.”’ Maria continued her husband’s story. “I believed her. I still do.” Sergio said. There was a brief silence, then Maria, her hands moving across her chest, said what she didn’t want Sergio to have to say again. “She died a few days later.”
www.who.org/en/ www.who.org/en/ • Malaria is a parasitic disease caused by a protozoan that replicates within red blood the cells (RBCs). The parasite is transmitted by a mosquito. Endemic malaria happens mainly in tropical climates where the mosquito is normally found. • Countries at risk are those where mosquito transmission is possible but not happening currently. Seasonal outbrakes (mainly in summer months) have been reported in places such as Switzerland, England and New Jersey.
www.who.org/en/ • More than 100,000 people of all ages die of malaria each year according to the World Health Organization (WHO). Malaria is the second most devastating infectious disease in the world after AIDS. • In 1980 malaria was endemic to 11 countries in the world. Currently, malaria transmission by mosquitoes happens in 107 countries according to the WHO.
Level 1 QuestionsBiology of Malaria • Which are the etiologic agents of malaria? • Which species of the mosquitoe is responsible for transmitting the disease? • Describe the parasite’s life cycle.
Online Resources on Malaria CDC Malaria Medline Plus NIH Medline Plus Tutorial NIH Malaria Triad: Genetics & Genomics WHO/TDR Malaria Database
Red blood cells (RBCs) infected with Plasmodium falciparum become sticky and tend to adhere to the inner wall of blood vessels. Sequestred RBCs may not be evident in a smear of peripheral blood at the early onset of infection when the ammount of infected RBCs is low (low parasitemia). Animated movie: sequetred Rbcs infected With P. Falciparum (www.whei.edu.au) Click here view videos Penetrate and Burst
Microscopic identification of malaria in peripheral blood requires an experienced microscopist, especially at low parasitemias. Both thick and thin blood smears should be performed in microscope slides to assess parasitemia. Thin smear preparation video demonstration: (vet.upenn.edu) Side of fingertip Click here
Thick and Thin Blood Smears deep view of blood Thick blood smear Thin blood Smear Sinle-layer of RBCs adapted from www.cdc.gov
Level 2 QuestionsMalaria Diagnosis • Establish a relationship between the plasmodium life cycle and the periodicity of the fever episodes. • When would be the best time to take a sample of peripheral blood for a smear? • Do antibody-screening tests detect DNA mutations in in Drug-resistant strains? • Design a PCR-based method for the identification of chloroquine resistant strains of P. falciparum?
Online Diagnostic Resource • DPDx - CDC - Division of Parasitic Diseases Complete Information on diagnostic methods for parasitic disease Click here And search on: Malaria and Diagnostic methods
www.cdc.gov • With the use of the insecticide dichlorodyphenyl-trichloroethane (DDT) and the drug chloroquine, malaria was eradicated from most urban areas around the world in the 1950s. Since the late 1970s the parasite began to develop resistance to chloroquine and the mosquito developed resistance to DTT.
There are different mechanisms of resistance related to different anti-malarial drugs. • Resistance to chloroquine and mefloquine in P. falciparum arose simultaneously in the early 1980s in South America and South east Asia. • Mutations in the pfmdr gene have been associated wit multi-drug resistance. This gene encodes a trans membran-efflux pump.
Malaria basics CDC Malaria MedlinePlus NIH MedlinePlus Tutorial NIH Malaria Triad: Genetics & Genomics WHO/TDR Malaria Database
Level 3 Questions • Using bioinformatics tools, find the protein sequence with higher similarity to the Plasmodium falciparum mdr. • Based on the sequence alignments of the mdr protein find potential differences in the structure responsible for drug resistance. • P. falciparum is more virulent than the other species that cause malaria in humans. Can this be explained in evolutionary terms? Compare the mdr protein sequence from different Plasmodium species.
Retrieving protein sequences • Click on the NCBI link on the right side. • Search for Plasmodiumfalciparum mdr • Select Protein: sequence database • Establish limits (ref seq) Change the display mode to FASTA NCBI
Write your keyword • Plasmodium • Click go.
You will obtain an incredible number of matches. • Let’s type Plasmodium falciparum.
Notice the number of hits is lower. Let’s try adding mdr (multidrug resistance) and click go.
Now you got only 19 hits. • Click on limits to look for curated data
Select from this pull down menu RefSeq. • Click go
This is your accession number, write it down. You will need this number if you need to retrieve this number. • Click on the accession number
The first part of the record consist of general protein information. • This number is the accession number of GenBank. If you click on it you will be directed to the gene sequence.
When you scroll down the record you will find information related to the protein function.
The last part of your record is the protein sequence. • Now, let’s compare this protein with other known proteins.
Click on best hits • To view the structure of
Select sort by taxonomy proximity • Observe that your list order is different
Biology Workbench • If you have no experience with Biology workbench click on the Tutorial, complete the tutorial before you start with this unit. • If you just want a quick review you may proceed to the next part. Biology Workbench Tutorial
Biology Workbench • Biology Workbench its free but you have to open an account. • Select the Biology Workbench link.